Laundry dryer control system



Dec. 20, 1960 w. A. RAY 2,965,367

LAUNDRY DRYER CONTROL SYSTEM Filed Aug. 20, 1956 2 Sheets-Sheet 1 4 4ZLIHIT 'srAT [7 25 BLOWER INVENTOR, W/LL/AM A. @AY

AT TUE/YE Y5.

Dec. 20, 1960 w. A. RAY

LAUNDRY DRYER CONTROL SYSTEM 2 SheetsSheet 2 Filed Aug. 20, 1956 lNVE/VT2 MAL/AM APAY 5/ MQLJAMJ I LII? F t LAUNDRY DRYER CONTROL SYSTEM WilliamA. Ray, North Hollywood, Calif assignor to General Controls Co., acorporation of (Ialifornia Filed Aug. 20, 1956, Ser. No. 605,171

18 Claims. (Cl. 263-43) This invention relates to laundry apparatus, andmore particularly to gas-fired dryers. Such dryers are loaded with wetor damp laundered material, the clothes being subjected to the heat ofthe products of the fuel combustion, as by the aid of a motor-operatedblower. Often the container in which the clothes are placed may be inthe form of a rotatable drum, producing a tumbler action. It is alsocommon to provide a timing arrangement, to preset the period duringwhich the drying process is effective.

It is one of the objects of this invention to provide, in a simplemanner, safeguards against hazardous conditions during attempted use ofthe dryer. For example, it is necessary, upon failure of the pilotflame, to ensure that the supply of fuel be interrupted, and the blowercontinued in operation for a short time to purge the tumbler ofunconsumed gases before the main burner flame is re -established.

It is also essential, after the dryer is turned ofi manually, tocontinue the blower operation for a short interval thereafter.

It is another object of this invention to ensure that the supply of fuelwill be interrupted upon failure of the pilot flame to ignite, within ashort period after the starting operation.

It is still another object of this invention, upon pilot flame failureand consequent accumulation of gas in the tumbler, to ensure againstenergization of the igniter until a sufficient time delay has occurredafter such pilot flame failure.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of oneembodiment of the invention. For this purpose, there is shown a form inthe drawings accompanying and forming a part of the presentspecification. This form will now be described in detail, illustratingthe general principles of the invention; but it is to be understood thatthis detailed description is not to be taken in a limiting sense, sincethe scope of this invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a schematic diagram of a control system incorporating theinvention, showing the apparatus in normal inactive position;

Fig. 2 is a fragmentary diagram of certain of the control elements shownin starting position; and

Fig. 3 is a view similar to Fig. 2, illustrating the control mechanismin the position wherein the dryer is in operation.

The control elements of the system are separated from the operatingelements of the dryer, by the aid of an enclosure or wall 1 (Fig. 1).Above the enclosure 1, there is shown the apparatus constituting thedryer, such as the main burner 2, pilot burner 3, blower and tumblermotor 4, a main fuel valve 5, and a pilot valve 6. The motor 4 operatesthe blower 4a and the tumbler 4b.

2,965,367 Patented Dec. 20, 1950 When the dryer is in operation, theblower and tumbler motor 4 is operating to blow the products ofcombustion from the main burner 2 through the rotating tumbler fordrying the contents of the tumbler. All this is now quite commonpractice.

Fuel is supplied through the main valve 5, when it is open, to theburner 2. The pilot valve 6 is adapted to supply fuel to pilot burner 3.Mains 7 and 8 serve to supply electrical energy for the various controldevices, and to the load operators, such as motors, valve-operatingelectromagnets, etc., hereinafter set forth.

The energizing circuit for the motor 4 is controlled by a circuitcontroller L. Whenever the circuit controller L is closed, and a doorswitch 9 is closed, the tumbler motor 4 is energized. The door switch 9is arranged to deenergize the motor 4 whenever the tumbler is beingloaded and unloaded, the door being open.

The circuit for the motor 4 can therefore be traced as follows: frommain 8, circuit controller L, connections it) and 11, motor 4, doorswitch 9, to the main 7.

The main valve 5, as well as the pilot valve s, are arranged to be opendby energizing electromagnets l2 and 13. The control circuit for thepilot valve 6 is interlocked with the control of the circuit for themain valve 5 so that the pilot valve 6 must be in open position, and thepilot flame 14 in existence, before the main valve 5 may be opened.

The control circuit for the pilot valve electromagnet 13 may be tracedas follows: from main 8, circuit controller L, connection 15, a secondcircuit controller M, connection 16, electromagnet 13, a limit switch17, to main 7. The limit switch 17 is responsive to high temperatures toensure shutting off the pilot. valve 6, as well as the main burner valve5 when excessive temperatures are encountered in the dryer tumbler. Thiscontrol circuit is rendered ineffective, due to circuit controller L,when the motor 4 is deenergized.

The manner in which circuit controllers L and M are opened and closedwill be described hereinafter.

Let us assume that the circuit controllers L and M are closed (see Fig.3). Closing of controller L immediately causes the motor 4 to operate.These circuit controllers also complete the circuit for the pilot valveelectromagnet 13 as hereinbefore traced. As will be explainedhereinafter, the circuit controller M is prevented from closing for aperiod after the motor 4 is energized. In this way, it is assured thatthere will be a purge period at the beginning of a drying cycle.

An igniter 18 for the pilot burner 3 is energized whenever theelectromagnet 13 is energized through the following circuit: main 8,circuit controller L, connection 15, circuit controller M, connection16, connection 19, normally closed circuit controller 20, the primarywinding 21 of a step-down transformer 22, to the main 7. The secondarywinding 23 of transformer 22 is connected to the igniter 18, andfurnishes a large current to the igniter. Accordingly, when the circuitcontrollers L and M are in closed position, the igniter 18 is energizedand the pilot burner 3 is lighted and the flame 14 is established.However, this can occur only when both circuit controllers L and M areclosed, ensuring a delay after the motor 4 is energized.

The main valve electromagnet 12 has an energizing circuit through anormally open circuit controller 24 which is closed in response to theexistence of a pilot flame 14, as hereinafter described. This main valvecircuit is also controlled by a thermostat 25 which en sures that themain burner 2 will be extinguished when a limiting temperature isreached without otherwise closing down the system. The complete circuitfor the main valve electromagnet 12 may be traced as follows: from main8, circuit controllers L and M, connections 16 and 3 19, circuitcontroller 24, connection 26, electromagnet 12, thermostat 25, doorswitch 9, to the main 7.

If the pilot flame I4 is not established, the circuit controller 24remains in open position. This is accomplished by a safety systemincluding a thermocouple 27 which, in a well-known manner, serves toenergize an electromagnet coil 28 mounted on a U-shaped core 29. TheU-shaped core 29 is mounted on an arm 30 fastened to a rotatable shaft31. The arm 39 is resiliently urged in a counterclockwise direction bythe aid of a spring 32, and is brought against a stop 33 as indicated inFig. 1.

Pivoted on the shaft 31 and freely rotatable with respect thereto is anarm 34. This arm 34 carries an armature 35 adapted to cooperate with thecore 29 and to be held in attracted position whenever the electromagnetcoil 28 is energized. The arm 34 is reciprocated at uniform rate; forexample at the rate of once per minute in a manner to be hereinafterdescribed, so as to advance the armature 35 counterclockwise intocontact with the core 29, and then to move it in a clockwise direction.If the coil 28 is energized, movement of the arm 34 in a clockwisedirection during its cycle will rotate the shaft 31 in the samedirection because arm 30 and core 29 will be moved together with arm 34.If, however, the coil 28 is not energized, due to the absence or failureof the pilot flame 14, then the shaft 31 is not reciprocated since thearmature 35 simply moves away from the core 29. There may be subsequentreciprocations of arm 34, until such time as core 29 sticks to armature35.

Assuming that the coil 28 is energized in response to the existence ofthe pilot flame 14, the circuit controller 24 is closed in response to asufficient angular movement of the arm 34 about the axis of shaft 31.Accordingly, the main valve is opened, since the circuit previouslytraced is completed, and the burner is in operation.

In order to operate the circuit controller 24, an actuator arm 36mounted on the shaft 31 is operated to cause contact between the contactpoints of the circuit controller 24. At the same time, in response tothe energization of the electromagnet coil 28, the circuit controller26B is opened to deenergize the igniter 18. This is accomplished by theaid of a bar or rod 37 passing diametrically through a large clearanceaperture 38 in the shaft 31, and urging one of the arms of circuitcontroller 29 toward the right to open it. This bar or rod is moved inthe same direction as shaft 31 when this shaft turns in a clockwisedirection. The bar may be independently moved in a clockwise directionto open this circuit controller, because of the large clearance betweenthe aperture 38 in the shaft 31, and the bar. The bar thus forms adetent preventing closing of switch 20 unless the bar or rod is in thevertical position of Fig. 1. The position of the detent, holding switch20 open, is illustrated in Fig. 3.

The bar 37 is retained against withdrawal from shaft 31 by the aid ofupset portions 39 on the bar.

The reciprocating movement of lever 34 is accomplished by the aid of atimer motor S, also labelled 40, which operates a timer shaft T. Thecircuit for the timer motor 40 is completed at the same time as motor'4is energized, through the following circuit: from main 8, circuitcontroller L connection 10, motor S, connection 50, door switch 9, tothe other main 7. Timer shaft T is provided with a cam 41 adapted tooperate a spring arm 42 anchored at its lower end. This spring arm 42 atits upper end is connected by a link 43 to the arm 34. As the shaft Tturns through one revolution, the arm 34 is likewise reciprocatedthrough a cycle. This controller L serves to initiate operation of motor40, as well as tumbler motor 4.

When the core 29 is picked up by the armature 35 due to energization ofthe coil 28, the degree of angular movement of the arm 34 is restricted.This is provided by a lock arrangement including a shaft 44. This shaft44 is adapted to be angularly moved in a c0UJ1t wise direction when thearm 30 is moved in a clockwise direction. This is accomplished by theaid of a screw 45, mounted on the arm 30. This screw 45 has a reducedend engaging in a recess or slot 46 of a collar 47 mounted on the shaft44. The collar 47 carries a locking pin 48 which can cooperate, asindicated in Fig. 3, with the screw 49 carried by the arm 34.Accordingly, the arm 34 can no longer move in a counterclockwisedirection since pin 48 acts as an abutment against such motion.Therefore, the rotation of the cam shaft T at the rate of one revolutionper minute, for example, merely oscillates the arm 34 through a limitedangle as indicated by the phantom lines in Fig. 3. This is insufiicientto open the circuit controller 24.

In starting the operation of the dryer, use is made of a cam 51 mountedon a shaft I, which cam serves to operate the circuit controllers L andM in sequence. This cam has a high portion urging the circuit controllerL to the open position of Fig. 1. This high portion has an opposite endwhich can urge the circuit controller M to closed position. In theposition of Fig. 1, both circuit controllers L and M are open. A spiralspring K anchored at its outer end, is connected at its inner end toshaft J, and urges the shaft and its cam 51 continuously in a clockwisedirection. It is necessary for the spiral spring K to move the cam 51clockwise through a small angle to permit the circuit controller L toclose, and to urge the circuit controller M to closed position. Thisoccurs in sequence, the circuit controller L closing before the circuitcontroller M is closed. These circuit controllers operate in response tothe expansion of spring K. A time delay is interposed between the twopositions of the cam 51 to ensure that the blower and tumbler motor 4may be operated for a short interval before the main burner 2 is ignitedin response to the closing of the circuit controller M. This time delayis effected by the aid of a lever Q which temporarily restrains an arm Iattached to shaft J.

In the inactive position, the shaft J is restrained by the aid of a stoppin P mounted on a ratchet wheel F and cooperating with the arm I. Bothcircuit controllers L and M are open in this position. Ratchet wheel Fis freely rotatable about the shaft 1, so that the wheel F may be movedin a clockwise direction, as hereinafter described, thereby moving pin Pout of restraining position, and permitting the spring K to move cam 51.

A setting pointer H is mounted on the wheel F. It is shown in Fig. 1 ascooperating with a dial 52 indicating the Off position. In thisposition, the pin P is active to restrian the shaft J "against theaction of the spring K to maintain both circuit controllers L and M inthe open position. The pointer H serves to determine the period ofoperation of the system. How this is accomplished will now be described.

In setting the apparatus to a selected time interval, the pointer H ismoved clockwise to a starting position, such as shown in Fig. 2.Thereafter the counterclockwise or reverse movement of the wheel Foccurs in a step-by-step manner, at the rate of one tooth per minute,until the pin P moves the arm I to the open circuiting position inFig. 1. Thus the pointer H and the wheel G cooperate with motor 40 forsetting the period of operation of both motors 4 and 40. The period ofoperative engagement of the circuit controllers L and M are also set bythis means.

This step-by-step movement is effected by an advancing pawl C. A holdingpawl B is used to hold the wheel F in the position to which it has beenadvanced.

The advancing pawl C is mounted upon an arm R which is anchored on ashaft 53. This arm R is adapted to be reciprocated by a cam 54 mountedon the timer shaft T. Accordingly, as soon as the timer shaft T isrotated once per minute by the motor 46), the wheel F is advanced onestep per minute.

When it is desired to move the pointer H manually for a settingoperation in a counterclockwise direction, the pawls B and C do nothinder such movement.

In order to make it possible to adjust the pointer H by clockwisemovement of the pointer to any desired position, the pawls C and B mustbe moved out of operative position. This is effected by the aid of ashaft A carrying a lifting cam 55. This shaft is adapted to be rotatedin a clockwise direction by the aid of a conventional pushbuttonmechanism 56. The lifted positions of the pawls C and B are indicated inFig. 2, which illustrates the starting operation. After the pointer H ismoved to the starting position, the pushbutton 56 is released, and pawlsC and B re-eng-age wheel iF (see Fig. 3.)

In order to delay the energization of the circuit for the valves 5 and 6and for the igniter 18 until a period of time has elapsed afterinitiation of operation, the shaft J is restrained against movementbeyond a position in which the circuit controller L is closed. This iseffected by the arm I engaging the upper surface of an arm 70 of delaylever Q. The arm 70 serves as a detent for arm I. This delay lever Q isconnected by a friction slipping clutch with shaft 53 upon which the armR is moutned. In this way, the lever Q may be moved, for a purpose to behereinafter described, independently of arm R.

Soon after the timer motor 40 is energized by the closing of the circuitcontroller L, the delay lever Q is moved outwardly in a clockwisedirection, through the slip clutch mechanism, by the aid of the arm R,so as to free the arm I from the starting position of Fig. 2. The arm Ithus assumes another position corresponding to that shown in Fig. 3, inwhich the circuit controller M is closed, in sequence after circuitcontroller L is closed. The time delay between closing of circuitcontroller M and the movement of the lever Q in a clockwise direction tofree arm I is provided by the slow rotation of shaft T. This time delaymay be as much as one-half minute. After arm I is thus freed, the springK urges the cam 51 to the position of Fig. 3, and both circuitcontrollers L and M are closed. Thus, after circuit controller I. isclosed, energizing the timer motor 40, there is a delay corresponding tothe operation of cam 54 to move the delay lever Q out of contact witharm I. The contacting position is shown in Fig. 2. This occurs beforethe circuit controller M is permitted to close.

The delay lever Q is provided with a stationary stop pin BB operating onthe horizontal arm of the lever Q to prevent the lever from moving toofar in a counterclockwise direction.

After the lever Q is moved clockwise out of the way, the pointer H andratchet wheel F are moved, as hereinbefore described, in acounterclockwise direction by pawl C.

When the wheel F is sufficiently advanced in this mannet to a positioncorresponding to zero minutes on the dial 52, the pin or actuator Ppicks up the arm I and causes opening of the circuit controller M. For aperiod corresponding to the angular distance between zero minutes andthe Off position, the blower motor 4 and the timer motor 40 continuetheir operation, due to continued closing of circuit controller L. Thiscontinues until the Off position of Fig. 1 is reached. In this positionthe cam 51 reaches its extreme counterclockwise position, openingcircuit controller L. The pin P thus operates as an actuator for movingthe circuit controllers L and M to initial position. The delaycorresponding to the distance between zero and Off positions causespurging of the dryer of the gases; and at the conclusion of the purgingoperation, the dryer is returned to the inactive position of Fig. 1.Since the opening of circuit controller L occurs upon completion of aforward movement of arm R, the stopped position of shaft T is alwaysthat shown in Fig. 1.

Arm I moves past the lower surface of arm 70 of lever Q when the Offposition is approached. This occurs after pin P picks up the arm I fromthe position of arm I of Fig. 3. Since the lower surface of arm 70 isinclined, the delay lever Q is moved by arm I out of the path of the armI. This is permitted by the slip clutch 53.

It is desirable to permit manual turnoff of the dryer even before thepreset time for drying is consumed. This is accomplished by manuallymoving pointer H in a counterclockwise direction to the Off position, asshown in Fig. 1. Then should the pointer H be moved again to a startingposition, it is essential to ensure that the motor 4 be operated for ashort time before circuit controller M closes.

In order to introduce this delay, a cam AA is mounted on the wheel F.This cam just before the Off position is reached, rotates the delay armQ in a counterclockwise direction by coacting with the raised portion 57of the horizontal arm of delay lever Q. The arm I has by that timepassed beyond the vertical arm '73 of delay lever Q. This operationmoves the lever Q in position for interposing a stop against clockwisemovement of arm I. This is necessary since when pointer H is manuallymoved to Off position, shaft T may stop at any position, even one inwhich lever Q is in the releasing position of Fig. 3. Accordingly,irrespective of the angular position of the time shaft T, the delaylever Q is positively placed in operative position by cam AA, so thatthere is a subsequent delay in the closing of the circuit controller Mby temporarily restraining arm I. Of course, :as soon as circuitcontroller L is closed, when a new drying period is begun, the shaft Tis rotated, and the delay lever Q will be moved out of the way when cam54 moves arm R in a clockwise direction. This delay corresponds to aninterval of between fifteen seconds to one minute and fifteen seconds,depending upon the angular position of the shaft T when the dryer ismanually turned 013.. In other words, a minimum of fifteen seconds forthis operation is represented by the position of the shaft T in Fig. l,for then it will take only fifteen seconds to move the arm R to theright. If the shaft T should be in a position where the cam 54 isstopped in a position from that shown in Fig. 1, it will take one minuteand fifteen seconds for the arm R to move the lever Q out of restrainingposition.

Provisions are made to ensure a delay in the deenergization of theblower and tumbler motor 4 after a pilot frame and main burner failureto ensure purging before the main burner 2 can be lighted. Thus, assumethat the pilot flame 14 is extinguished: the spring 32 after a shortinterval will puil the core 2% to the position of Fig. 1, extinguishingthe main burner 2, and the cam 41 will then reciprocate the arm 42through a full stroke. This arm 42 operates a mechanism for rotating theshaft I in a counterclockwise direction independently of wheel F, tobring the circuit controllers L and M to an open position after a delayinterval, to open circuit controllers L and M to return them to theinitial position of Fig. 1. After this delay, the i niter switch 20 ispermitted to close to energize igniter 21.

For this purpose, use is made of another ratchet wheel G free to rotateupon the axis of shaft J. This ratchet wheel G is normally urged byspring CC in a clockwise direction. In normal operation, the spring isprevented from moving the ratchet wheel G against the advancing pawl Eand the pawl D. Advancing pawl E is mounted upon the oscillating arm 42.The timer motor S is effective, upon pilot flame failure, to rotate theshaft J, and the advancing pawl E moves the ratchet wheel G stepbystepin a counterclockwise direction until the pin DD carried by the Wheel Gmoves the arm EE for moving cam 51 to a position where the circuitcontrollers L and M are opened in succession, shutting down the system.This delay may be about five minutes. If, before this happens, the pilotflame should be re-established, the arm 7 42 is restrained againstreciprocation suflicient to rotate ratchet wheel G.

About two minutes prior to ultimate shutdown, a cam 58 carried on shaftI returns to the position shown in Fig. 1. This cam normally urges bar37 to the position shown in Fig. 3, ensuring against closing of theigniter circuit controller 20. When the cam 58 is moved by arm EE to theposition of Fig. l, the bar 37 no longer restrains the circuitcontroller 2%) against closing. Accordingly, the igniter 18 may beenergized, as well as the pilot valve operating electromagnet 13. Thus apurge period of about three minutes is effective to ensure that nounconsumed gases remain in the tumbler when the pilot burner is againignited.

The setting of the apparatus to a starting position is illustrated inFig. 2. In this position, the pushbutton mechanism 56 is depressed so asto release both sets of pawls CB and ED. While the button 56 isdepressed, the pointer H and the corresponding ratchet wheels F and Gare moved by hand to the starting position of Fig. 2, The motors 4 andii are energized. The delay lever Q operates as a detent against the armI so as to restrain clockwise movement of the shaft I until thefollowing movement of the arm R to the right by the timing motor 40. Inthe position shown in Fig. 2, the timing motor circuit is completedthrough the circuit controller L, as well as the tumbler and blowermotor 4. Until the timer motor rotates sufliciently to move the delaydetent Q out of the path of arm I, the pilot valve electromagnet 13 andigniter 15 are not energized.

As soon as this setting is performed, the pushbutton 56 is released. Thetimer motor 49 now gradually moves the ratchet wheel F in acounterclockwise direction. An intermediate position is shown in Fig. 3.In this position, both of the circuit controllers L and M are in closedposition under the influence of the spring K.

When the pointer H reaches the dotted line position of Fig. 3, the pin Phas moved the arm I to a position just prior to the opening of thecircuit controller M. The circuit controller L, however, remains closeduntil the pointer H reaches the Oil position of Fig. 1. In thisposition, the arm I, through shaft I, has moved the cam '1 to a fullopen position.

During the running position, the arm 3% is reciprocated through a smallangle as indicated by the phantom lines in Fig. 3 since fullreciprocation is not permitted by virtue of the locking pin 48.Accordingly, the time delay ratchet wheel G is not actuated.

As heretofore explained, in the event of pilot flame failure, theratchet wheel G is moved in a counterclockwise direction, pin DD pickingup arm EE and ultimately opening the circuit to the pilot valveelectromagnet 13. A few minutes before that occurs, the igniter 18 willbe conditioned to be energized by circuit controller Ztl, ensuring thatall gases are purged from the tumbler before the pilot flame may bere-established.

The inventor claims:

1. In a control system for a clothes dryer heated by fluid fuel andhaving a main burner, an electricallyoperated main valve, a pilotburner, an electrically-operated pilot burner valve, a blower, and motormeans for the blower: a pair of circuits, each including a circuitcontroller respectively for energizing the motor means and the pilotvalve; a first ratchet wheel mechanism movable to a starting position topredetermine the period of energization of said circuits, and movable toa starting position; means responsive to the existence of a pilot flameto energize the main valve; means operated in response to the movementof the first mechanism to starting position for placing the firstcircuit controller in active position to energize its respectivecircuit; means for providing a delayed actuation of the second circuitcontroller to active position to energize its respective circuit; meansfor intermittently moving the first mechanism in a direction towardstopping position and for operating the 8 second"circuit controller todeener gizing positionnear the completed movement in said direction;said movement at stopping position causing the first circuit controllerto move to deenergizing position; and a second ratchet wheel mechanismoperated 'in response to pilot flame failure for independently operatingthe second and first circuit controllers sequentially to deenergizingpositions.

2. In a control system: first and second control circuits, respectivelyincluding first and second circuit controllers; an actuator movable froman initial position to a starting position; means responsive to saidmovement for operating the first of said circuit controllers; mechanismaffected by said circuits operating to move said actuator in a reversedirection; a detent operated by said mechanism to prevent operation ofthe second circuit controller when the actuator is moved to a startingposition; means responsive to movement of the actuator toward initialposition to release said detent and to operate the second circuitcontroller to closed position; and means responsive to the movement ofthe actuator in said reverse direction to initial position forsequentially opening the second and first circuit controllers.

3. In a control system for a clothes dryer heated by fluid fuel andhaving a main burner, an electrically-operated main valve, a pilotburner, an electrically-operated pilot burner valve, anelectrically-operated igniter for the pilot burner, a blower, and motormeans for the blower: circuit control means for first energizing themotor means, and then the pilot valve and igniter, said circuit controlmeans including a normally closed supplemental circuit controller forthe igniter; means responsive to the existence of a pilot flame toenergize the main valve and to open said supplemental circuitcontroller; a detent restraining said circuit controller againstclosing; and time delay means operating in response to pilot flamefailure for rendering said detent ineffective.

4. In a control system for a clothes dryer heated by fluid fuel andhaving a main burner, an electrically-operated main valve, a pilotburner, an electrically-operated pilot burner valve, anelectrically-operated igniter for the pilot burner, a blower, and motormeans for the blower: circuit control means for first energizing themotor means, and then the pilot valve and igniter, said circuit controlmeans including a normally closed supplemental circuit controller forthe igniter; means responsive to the existence of a pilot flame toenergize the main valve and to open said supplemental circuitcontroller; a detent restraining said circuit controller against closingand time delay means operating in response to pilot flame failure forrendering said detent ineffective and for subsequently deenergizing themotor means and pilot valve.

5. In a control system for a main burner, an electricallyoperated mainburner valve, a pilot burner, an electricallyoperated pilot burnervalve, and an electrically energized igniter for the pilot burner: 21first circuit including a first circuit controller for the pilot burnervalve and the igniter; a second circuit including a second circuitcontroller for the igniter; means responsive to the existence of a pilotflame for energizing the main burner valve, and for deenergizing themain burner valve upon pilot flame failure, as well as for opening thesecond circuit closure; and means for delaying closing of said secondcircuit controller upon pilot flame failure, including a detent bar, arod through which the detent bar passes with clearance to permit themain valve to be deenergized, and timing means for moving the detent barto releasing position.

6. In a control system for a main burner, an electricallyoperated mainburner valve, a pilot burner, an electricallyoperated pilot burnervalve, and an electrically energized igniter for the pilot burner: anelectromagnet including an armature; means responsive to the existenceof a pilot flame for energizing the electromagnet; means periodicallyplacing the armature into attracted position with respect to theelectromagnet while the electromagnet is unenergized, and thereafterangularly moving the electromagnet and the armature together to anoperative position; means limiting angular movement of saidelectromagnet and armature, while the electromagnet is energized, fromsaid operative position; a first circuit having a first circuitcontroller for the main burner valve; a second circuit having a secondcircuit controller for the igniter; said operative position causing thefirst circuit controller to be closed and the second circuit controllerto be opened; and means operative upon pilot flame failure, to cause thesecond circuit controller to close after a time interval.

7. In a control system for a main burner, an electricallyoperated mainburner valve, a pilot burner, an electricallyoperated pilot burnervalve, and an electrically energized igniter for the pilot burner: anelectromagnet including: an armature; means responsive to the existenceof a pilot flame for energizing the electromagnet; means providing acommon shaft serving as a pivotal support for the electromagnet and thearmature; means for angularly moving the armature about said support,toward and from the electromagnet while the electromagnet isdeenergized, and then after energization, for bringing the armature andthe electromagnet to an operative position; means limiting angularmovement of said shaft, While the electromagnet is energized, from saidoperative position; a first circuit having a first normally open circuitcontroller for the main burner valve; a second circuit having a secondnormally closed circuit controller for the igniter; means including saidshaft, in operative position, operating to close the first circuitcontroller; a rod passing through the shaft with clearance andresponsive to angular movement of the shaft for operating the secondcontroller to open position; means restraining the rod against movement,to maintain the second circuit controller open; and time delay means forreleasing said rod after the electromagnet is deenergized.

8. In a control system for a heater utilizing fluid fuel and having aspace through which the products of combustion pass, a main burner, ablower for the space, a pilot burner, an electrically-operated pilotburner valve, an igniter for the pilot burner, and motor means foroperating the blower: a circuit having a circuit controller forenergizing or deenergizing the igniter; a shaft; a rod angularly movedby the shaft in response to establishment of a pilot flame to open thesaid circuit controller; and delay means for moving the rod to close thecircuit controller upon pilot flame failure.

9. The combination as set forth in claim 8, in which the delay meansincludes a step-by-step mechanism; a motor for operating said mechanism;and means for causing the motor to be operatively coupled to themechanism upon pilot flame failure.

10. The combination as set forth in claim 8, in which the rod projectsthrough a clearance hole in the shaft, to permit independent movement ofthe rod about the axis of the shaft.

11. In a control system for a clothes dryer heated by fluid fuel andhaving a main burner, an electrically operated main valve, 2. tumbler, ablower, and motor means for the blower: a timer motor; a first and asecond circuit controller; a movable mounting having provisions foroperating the circuit controllers, and biased to one position in whichboth circuit controllers are closed; said mounting being retractable toopen the second and first controllers respectively in spaced sequence;first circuit means dependent upon said first controller being closedfor operating the timer motor and said motor means; second circuit meansdependent upon the second circuit controller being closed forconditioning said electrically operated main valve for energization;movable dial means having a projection engageable with the mounting forholding the mounting in fully retracted position, said dial means beingmovable in one direction away 10 from engaging position; means operatedby the timer motor for slowly moving the dial means in the otherdirection; a movable locking bar holding said mounting in anintermediate position in which said second circuit controller is openand said first circuit controller is closed; and means initiated uponoperation of said timer motor for retracting said locking bar after aperiod of time.

12. In a control system for a clothes dryer heated by fluid fuel andhaving a main burner, an electrically operated main valve, a tumbler, ablower, and motor means for the blower: a timer motor; a first and asecond circuit controller; a movable mounting having provisions foroperating the circuit controllers, and biased to one position in whichboth circuit controllers are closed; said mounting being retractable toopen the second and first controllers respectively in spaced sequence;first circuit means dependent upon said first controller being closedfor operating the timer motor and said motor means; second circuit meansdependent upon the second circuit controller being closed forconditioning said electrically operated main valve for energization;movable dial means having a projection engageable with the mounting forholding the mounting in fully retracted position, said dial means beingmovable in one direction away from engaging position; means operated bythe timer motor for slowly moving the dial means in the other direction;a movable locking bar holding said mounting in an intermediate positionin which said second circuit controller is open and said first circuitcontroller is closed; and means operated by said timer motor forreciprocating said locking bar between holding and releasing positions;said locking bar having reset means operated upon return movement ofsaid mounting to fully retracted position, whereby said locking bar isoperative for subsequent operations despite manual overriding of saiddial means.

13. In a control system for a clothes dryer heated by fluid fuel andhaving a main burner, an electrically operated main valve, a pilotburner, an electrically operated pilot burner valve, a tumbler, ablower, and motor means for the blower: a timer motor; a first and asecond circuit controller; a movable mounting having provisions foroperating the circuit controllers, and biased to one position in whichboth circuit controllers are closed; said mounting being retractable toopen the second and first controllers respectively in spaced sequence;first circuit means dependent upon said first controller being closedfor operating the timer motor and said motor means; second circuit meansdependent upon the second circuit controller being closed forconditioning said electrically operated main valve for energization andfor operating said electrically operated pilot burner valve; meanscooperable with said second circuit means for preventing energization ofsaid electrically operated main valve in response to failure of a flameat said pilot burner; movable dial means having a projection engageablewith the mounting for holding the mounting in fully retracted position,said dial means being movable in one direction away from engagingposition; means operated by the timer motor for slowly moving the dialmeans in the other direction; safety means operable only during pilotburner flame failure and operated by said timer motor for moving saidmounting to retracted position independently of said dial meansprojection; and means operated by resetting of said dial means forautomatically resetting said safety means.

14. In a control system for a clothes dryer heated by fluid fuel andhaving a main burner, an electrically operated main valve, a pilotburner, an electrically operated pilot burner valve, a tumbler, ablower, and motor means for the blower: a timer motor; a first and asecond circuit controller; a movable mounting having provisions foroperating the circuit controllers, and biased to one position in whichboth circuit controllers are closed; said mounting being retractable toopen the second and first for operating the timer motor and said motormeans;

second circuit means dependent upon the second circuit controller beingclosed for conditioning said electrically operated main valve forenergization and for operating said electrically operated pilot burnervalve; means cooperable with said second circuit means for preventingenergilation of said electrically operated main valve in response tofailure of a flame at said pilot burner; movable dial means having aprojection engageable with the mounting for holding the mounting infully retracted position, said dial means being movable in one directionaway from engaging position; means operated by the timer motor forslowly moving the dial means in the other direction; safety meansoperable only during pilot burner flame failure and operated by saidtimer motor for moving said mounting to retracted position independentlyof said dial means projection; means operated by resetting of said dialmeans for automatically resetting said safety means; a movable lockingbar holding said mounting in an intermediate position in which saidsecond circuit controller is open and said first circuit controller isclosed; and means operated by said timer motor for reciprocating saidlocking bar between holding and releasing positions; said locking barhaving reset means operated upon return movement of said mounting tofully retracted position,

whereby said locking bar is operative for subsequent operations despitemsirnarevemdin of said dial means.

15. in a control system: a first ratchet wheel; a first pawl foroperating the first ratchet wheel; a second ratchet wheel; a second pawlfor operating the second ratchet wheel; a shaft; a cam operated by theshaft; a circuit controller operated by the cam; resilient means urgingthe cam in one direction; a'first actuator carried by the first wheel,which actuator upon sufiicient advance of the wheel, serves to move theshaft angularly against the force of the resilient means; a timer meansconnected to the first pawl for intermittently advancing the firstactuator; said timer having means for advancing the second ratchet wheelto move the second actuator; and condition-responsive means forrendering the said means for advancing the second ratchet wheelineffective.

16. Ina control system: a first ratchet wheel; a-first pawl foroperating the first ratchet wheel; a second ratchet wheel; a second pawlfor operating the second ratchet wheel; a shaft; a cam operated by theshaft; a circuit controller operated by the cam; resilient means urgingthe cam in one direction; a first actuator carried by the first wheel,which actuator upon sufficient advance of the wheel,- serves to movetheshaft angularly against the force of the resilient means; a timermeans connected to the first pawl for intermittently advancing the firstactuator; said timer having means for advancing the second ratchet wheelto move the second actuator; and condition-responsive means forrendering the said means for advancing the second ratchet wheelineffective; said circuit controller including a pair of switchessequentially operated by the cam; said first ratchet wheel beingsettable to determine the period required to cause the cam to operate.

17. The combination as set forth in claim 16, in which the setting ofthe first ratchet wheel causes the resilient means to move the cam tooperate one of the switches; and means interposing a delay before thesecond switch is operated.

18. The combination as set forth in claim 16, in which the setting ofthe first ratchet wheel causes the resilient means to move the cam tooperate one of the switches; said time-r means including a reciprocatingarm; a detent for the shaft; a friction clutch between the shaft and thedetent; and means operated by the setting of the first ratchet wheel tomove the detent into restraining position; the reciprocation of the armserving to move the detent out of restraining position.

References Cited in the file of this patent UNITED STATES PATENTS Re.24,235 Geldhof et al Nov. 6, 1956 2,174,275 Raney Sept. 26, 19392,427,178 Aubert g Sept. 9, 1947 2,519,889 Crawford Aug. 22, 19502,575,289 Nycum et a1 Nov. 13, 1951 2,678,814 Geldhof et al May 18, 1954

